Kristensen, Hanne L. and Thorup-Kristensen, Kristian    (2008) Roots below one meters depth are important for nitrate uptake by annual crops.  [Rødder under én meters dybde er vigtige for et-årige afgrøder's optagelse af nitrat.]   In: Ma, L.; Ahuja, L.R. and Bruulsema, T.W. (Eds.)   Quantififying and understanding plant Nitrogen uptake for systems modeling (ISBN 13:978-1-4200-5295-4).  CRC Press, chapter 11, pp. 245-258.